Nice article and great explanation in the article... too bad they didn't actually test it for performance... 😉 Both of the following UDF's render identical execution plans and they both take turns winning on my desktop. That also means that compared to the inline code, they both make some nasty sucking sounds. 😛 I got the function code below from the article.

[font="Courier New"]

---

--===== Create a scalar function with SchemaBinding 

 CREATE FUNCTION dbo.ComputeNumSB(@i INT)

RETURNS INT

   WITH SCHEMABINDING

  BEGIN

        RETURN @i * 2 + 50

    END

GO

--===== Create a scalar function without SchemaBinding

 CREATE FUNCTION dbo.ComputeNum(@i INT)

RETURNS INT

  BEGIN

        RETURN @i * 2 + 50

    END

GO

--===== Create and populate the Tally table on the fly

 SELECT TOP 1000000 --equates to more than 30 years of dates

        IDENTITY(INT,1,1) AS N

   INTO dbo.Tally

   FROM Master.dbo.SysColumns sc1,

        Master.dbo.SysColumns sc2

--===== Add a Primary Key to maximize performance

  ALTER TABLE dbo.Tally

    ADD CONSTRAINT PK_Tally_N 

        PRIMARY KEY CLUSTERED (N) WITH FILLFACTOR = 100

--===== Allow the general public to use it

  GRANT SELECT ON dbo.Tally TO PUBLIC

GO

--===== Test more than once... the functions take turns winning.

     -- The inline code ALWAYS blows the functions away.

DECLARE @BitBucket INT

DECLARE @TestSize  INT

 SELECT @TestSize = 100000

SET STATISTICS TIME ON

 SELECT @BitBucket = dbo.ComputeNumSB(t.N)

   FROM dbo.Tally t

  WHERE t.N <= @TestSize

 SELECT @BitBucket = dbo.ComputeNum(t.N)

   FROM dbo.Tally t

  WHERE t.N <= @TestSize

 SELECT @BitBucket = t.N * 2 + 50

   FROM dbo.Tally t

  WHERE t.N <= @TestSize

SET STATISTICS TIME OFF

PRINT REPLICATE('=',80)

GO 6

---

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For those that don't know what a Tally table is, now would be a good time to learn. Please see the following article...

http://www.sqlservercentral.com/articles/T-SQL/62867/

I agree with most of the other's said here... a UDF is probably not the way to go here. An aux table or a bit of inline code is the way to go. Here's the run results from the code above...

[font="Courier New"]Beginning execution loop

SQL Server Execution Times:

CPU time = 8625 ms, elapsed time = 16175 ms.

SQL Server Execution Times:

CPU time = 8922 ms, elapsed time = 16226 ms.

SQL Server Execution Times:

CPU time = 78 ms, elapsed time = 78 ms.

================================================================================

SQL Server Execution Times:

CPU time = 8704 ms, elapsed time = 16103 ms.

SQL Server Execution Times:

CPU time = 8875 ms, elapsed time = 16358 ms.

SQL Server Execution Times:

CPU time = 78 ms, elapsed time = 76 ms.

================================================================================

SQL Server Execution Times:

CPU time = 8203 ms, elapsed time = 16051 ms.

SQL Server Execution Times:

CPU time = 8406 ms, elapsed time = 16075 ms.

SQL Server Execution Times:

CPU time = 78 ms, elapsed time = 94 ms.

================================================================================

SQL Server Execution Times:

CPU time = 8922 ms, elapsed time = 15994 ms.

SQL Server Execution Times:

CPU time = 8922 ms, elapsed time = 19858 ms.

SQL Server Execution Times:

CPU time = 78 ms, elapsed time = 81 ms.

================================================================================

SQL Server Execution Times:

CPU time = 8203 ms, elapsed time = 17882 ms.

SQL Server Execution Times:

CPU time = 8844 ms, elapsed time = 19245 ms.

SQL Server Execution Times:

CPU time = 94 ms, elapsed time = 86 ms.

================================================================================

SQL Server Execution Times:

CPU time = 8297 ms, elapsed time = 16888 ms.

SQL Server Execution Times:

CPU time = 8656 ms, elapsed time = 18983 ms.

SQL Server Execution Times:

CPU time = 78 ms, elapsed time = 79 ms.

================================================================================

Batch execution completed 6 times.

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